In a gas turbine engine, the combustor includes a combustor shell which defines the combustion chamber where the gas are ignited and the combustion takes place. The combustor shell may include one or more row of apertures, known as dilution holes, which allow a portion of the air from outside of the combustor shell to enter the combustion chamber and mix with the ignited gases. The flow of air going through the dilution holes, known as dilution flow, is taken from an external air supply cavity or plenum, and flows directly into the combustion chamber through the dilution holes. The combustor shell is typically lined with heat shields for protecting the combustor shell from the high temperatures generated by the combustion. The heat shields may be cooled using impingement jets formed by impingement holes in the combustor shell. Effusion holes may also be defined in the heat shields to further cool same. The dilution flow is independent and separate from the flow of cooling air passing through the impingement holes and effusion holes.
The areas surrounding the dilution holes may develop hot spots due to lack of cooling air and main stream, high heat load secondary flow structures. Accordingly, there is a need for an improved cooling scheme to provide cooling to the surrounding area of the dilution holes.